diff --git a/idl/SMESH_Mesh.idl b/idl/SMESH_Mesh.idl
index 4e7b2c561..5e1c948da 100644
--- a/idl/SMESH_Mesh.idl
+++ b/idl/SMESH_Mesh.idl
@@ -246,6 +246,12 @@ module SMESH
     ListOfGroups GetGroups()
       raises (SALOME::SALOME_Exception);
 
+    /*!
+     *  Get number of groups existing in the mesh
+     */
+    long NbGroups()
+      raises (SALOME::SALOME_Exception);
+
     /*!
      * Union of two groups
      *    New group is created. All mesh elements that are